Supposer a number of unobservable processes are executed to performa an information processing task. This research is on a method for deducing the organization of the processes from the accuracy and completion time of the task under various conditions. The method combines ideas from the additive factor method and the theory of scheduling, and applies to tasks involving a mixture of sequential and concurrent processes. A Stroop task and a letter naming task will be analyzed with the method. There is evidence that in each task, the processes are arranged in a critical path network. I plan to do further tests of this idea and to discover more details of the network for each task. The experiment on the Stroop effect will consider a question left open in a previous experiment, whether a subject can carry out two decisions concurrently under certain conditions. An extension of the additive factor method to accuracy data is proposed. The effects of experimental factors on the log of the probability of a correct response are considered. The effects are expected to be additive under certain conditions. In other words, an analog of the additive factor method is possible for log probability correct data. Experiments on letter naming and color naming using this procedure are proposed.